Metallic Electrical Outlet Boxes
Listed single and double gang metallic outlet and switch boxes with
metallic or nonmetallic cover plates may be used in bearing and nonbearing
wood stud and steel stud walls with ratings not exceeding 2 h. These
walls should have gypsum wallboard facings similar to those shown in
Design Nos. U301, U411 and U425. The metallic outlet or switch boxes
should be securely fastened to the studs and the opening in the wallboard
facing should be cut so that the clearance between the box and the wallboard
does not exceed 1/8 in. The surface area of individual metallic outlet
or switch boxes should not exceed 16 sq in. The aggregate surface area
of the boxes should not exceed 100 sq in. per 100 sq ft of wall surface. The
aggregate surface area of the boxes may be exceeded when Wall Opening
Protective Materials (CLIV) are installed according to the requirements of
their Classification.
Metallic boxes located on opposite sides of walls or partitions should be
separated by a minimum horizontal distance of 24 in. This minimum
separation distance between metallic boxes may be reduced when Wall
Opening Protective Materials (CLIV) are installed according to the requirements
of their Classification.
Metallic boxes should not be installed on opposite side of walls or partitions
of staggered stud construction unless Wall Opening Protective Materials
are installed with the metallic boxes in accordance with Classification
requirements for the protective materials.
